This invention relates generally to knob control devices, and more particularly to control knob devices including force feedback and/or additional input functionality.
Control knobs are used for a variety of different functions on many different types of devices. Often, rotary control knobs offer a degree of control to a user that is not matched in other forms of control devices, such as button or switch controls. For example, many users prefer to use a rotating control knob to adjust the volume of audio output from a stereo or other sound output device, since the knob allows both fine and coarse adjustment of volume with relative ease, especially compared to button controls. Both rotary and linear (slider) knobs are used on a variety of other types of devices, such as kitchen and other home appliances, video editing/playback devices, remote controls, televisions, computer interface controllers, etc. There are also many types of knobs that allow push-in or pull-out functionality to allow the user additional control over a device.
Some control knobs have been provided with force (kinesthetic) feedback or tactile feedback, which is collectively referred to herein as xe2x80x9chaptic feedback.xe2x80x9d Haptic feedback devices can provide physical sensations to the user manipulating the knob. Typically, a motor is coupled to the knob and is connected to a controller such as a microprocessor. The microprocessor receives knob position and direction signals from the knob sensor and sends appropriate force feedback control signals to the motor so that the motor provides forces on the knob. In this manner, a variety of programmable feel sensations can be output on the knob, such as detents, spring forces, or damping.
One problem occurring in control knobs of the prior art is that many of the well-known force feedback sensations, such as detents, are applied in simple ways that are often inadequate for dealing with some of the selection functions required from a knob, where often complex control over functions and options must be provided with limited knob motion. For example, selecting options from a menu and navigating between menus can be difficult for a user when only simple detents are output. The user may accidentally skip menus or selections or may have to move a cursor through many undesired selections to reach a desired selection.
The present invention provides haptic sensations for a rotational haptic feedback device such as a knob. Described haptic sensations take advantage of the limited motion of a rotational device such as a knob and provide greater control over selection and other operations.
More particularly, in one embodiment a method for providing a hill force effect for use with a force feedback device includes outputting a resistive force on a user manipulandum, such as a knob, contacted by a user and moveable in a degree of freedom. The resistive force is output when the user moves the knob in a particular direction toward a division between knob selections or menus. The resistive force is initially low in magnitude and increases in magnitude the further the knob is moved. As the knob is continued to be moved in the particular direction, the resistive force is removed and an assistive force is output on the knob. The division can be between two menus, for example, each menu having menu items selectable by the knob, said resistive force being output when the user moves between different menus.
In another aspect of the present invention, a method for providing a scrolling list for use with a force feedback device includes causing a display of a menu on a display device, the menu including menu items, where at least one menu item is not displayed concurrently with other menu items. A cursor is displayed for highlighting one of the menu items which can be selected using a manipulandum. The manipulandum, such as a knob, is moved to a border of the menu, and a spring force is output resisting motion of the knob out of the menu. A rate control mode is entered when the knob is moved to the border of the menu, where at least one undisplayed menu item is scrolled onto the display device at a rate determined by a distance that the knob is moved past the menu border. A detent force can be output when the cursor moves from one menu item to a different menu item. A jolt or detent output force can be output on the knob when each of the undisplayed items is scrolled onto the display screen.
In another aspect of the present invention, a method for providing a barrier force effect for use with a force feedback device includes sensing motion of a user manipulandum, determining that a barrier force is to be applied to the manipulandum in a particular direction beginning at a particular position, and outputting the barrier force that resists manipulandum motion in the particular direction. The barrier force increases in magnitude the further that the manipulandum is moved, the magnitude having a lower rate of increase in an initial region and a higher rate of increase past the initial region. For example, the magnitude increase can follow an exponential relationship. An initial oscillating force and/or a damping force can also be applied.
In another aspect of the present invention, a method for providing a jog shuttle control using force feedback includes outputting a first spring force on a rotary knob over an entire range of motion of the knob. The first spring force with a first stiffness biases the knob to an origin position. A second spring force has a second stiffness greater than the first stiffness and the second spring force biases the knob to the origin position. The second spring force is only output on the knob when the knob is in a particular range centered around the origin position. Preferably, a value or function implemented by a microprocessor is changed according to a rate control paradigm, where a rate of the change is determined by a distance of the knob from the origin position.
Other control models for a rotatable knob using haptic feedback are also described. For example, in one control model, a resistive force resists the turning of the knob unless the user moves the knob along the axis of rotation, e.g. the user pushes the knob. The resistive force is then ceased, allowing the user to rotate the knob while the knob has been pushed. In another control model, a first resistive spring force resists a rotation of the knob, and a second resistive force is instead output when the knob reaches a selection point in a direction against the first spring force. The second spring force can have a greater stiffness than the first spring force. A cast control model can provide a first force resisting a rotation of the knob in a first direction. An adjustment of a value or position is made when the user rotates the knob in the first direction to a first position and then rotates the knob in a second direction opposite to the first direction.
The present invention provides a variety of force models and force effects which are suitable for use with haptic feedback devices, especially haptic feedback rotary devices such as control knobs. Many of the force effects and models allow a user of a control knob to make selections of menu items, menus, and other options, as well as adjust values, in easier fashion than with control knobs of the prior art. The force effects of the present invention also reduce the amount of overshooting, unintentional selection, and other undesired motions that can occur with prior art haptic and non-haptic control knobs.